Ponds, streams, rivers, lakes, a massive salt water inlet? Whatcom County has it all. It also has Rainbow, Brown, Cutthroat (searun and land locked), Kokanee, Dolly Varden trout, Steelhead, King, Coho, Chum, Pink, Sockeye Salmon, Large Mouth and Small Mouth Bass, Carp, Walleye, Tiger Muskie (yep, you read that correctly Fazon Lake!!!), Blue Gil, Crappie, Flounder, Cod, Ling Cod, Rock Fish and a whole host of other salt water species that I’m probably forgetting.
You can also choose from high mountain lakes to tidal estuaries. One of the beauties of Whatcom County is that when it comes to nature It has pretty much everything other than a desert.
For Bellingham Bay I would use at least an eight weight rod with a good saltwater reel. Coho, Chum, and Pink Salmon are all possible here and you will be glad to have a heavier rod to land these powerful fish. An intermediate sink tip line was the best all around line that I used while fishing Bellingham Bay.
Any of the Candle Fish, Clousers in chartreuse and pink, as well as most of the salt water flies used for Sea Run Cutthroat will work in Bellingham Bay.
I have seen people use sea kayaks rigged for trolling catch Coho with fly rods as well as Pontoon Boats on calm days. Having a John Boat with an engine though is probably best if you want to really explore Bellingham Bay. I also know people that have used float tubes in Bellingham Bay, but I was always very leery of the potentially strong tides and winds and never tried it myself. I imagine if you stayed very close to shore and paid close attention to the tide and weather you would probably be fine. Needless to say a life jacket and very warm waders would be a must.
Boulevard Park is one of the largest parks in the city of Bellingham and the entire park runs along Bellingham Bay. Taylor Dock also connects the park with the north end of Fairhaven and can be fished from. This is an extremely popular spot in Bellingham though, so when I fished there I would try and hit in the morning on a weekday. When it is crowded casting with a fly rod is pretty much impossible. Also, Taylor Dock is fairly high, so if you do hook into something large like a Coho it might be pretty hard to land it. I have caught both Coho and Pink Salmon (odd years) here as well as Flounder. I had the best like in the morning during the incoming tide.
Another spot I had great luck at catching Pink Salmon in 2001 was at the Marine Park at the very end of Fairhaven on the south side of Bellingham. This is a much smaller park than Boulevard Park, but it juts right out into Bellingham Bay, so when the Pink Salmon are in during odd years you can often cast to them from shore during high tide. Look for either Pinks rolling on the surface or bait fish frantically breaking the surface. This is usually a good sign either Pinks and sometimes Coho too are feeding in the area. Coho and Pinks both seem to prefer low light conditions rather than direct sunlight, so early or evening high tides are best.
Lake Padden is a fantastic spot to fly fish for Rainbows, resident Cuttthroat, Kokanee, and Large Mouth Bass. It is perfect for a float tube or pontoon boat. Spring is when Lake Padden really shines in my opinion. Casting dry flies to rising fish, trolling nymphs, Wooley Buggers, and small white streamers have all worked well for me here. Chironomids aren’t my favorite way to fly fish, but they work very well under a strike indicator and long tippet as well here.
Whatcom Creek (the mouth in Heritage Maritime Park) is a tough spot to fly fish considering the crowds and aggressive seals that will rip salmon right off your rod. But you do have a shot at catching some very large Chum Salmon, Coho, and Pinks in the Fall and early Winter. It is pretty rare, but if you can catch it on weekday early in the morning on an incoming tide, especially after a heavy rain, the Chums will be in there thick.
If there are only a few or no people on the pier you can fly fish from there, though almost everyone uses a bait caster. There are a few spots on the other side of Whatcom Creek that you cast from as well.
This video is a very mixed bag and unfortunately doesn’t show anyone actually fly fishing the mouth of Whatcom Creek for Chums, but it does give a very good idea of what things there can be like. Including a nasty encounter with one of the salmon stealing harbor seals. Fly Fishing With Ladin is an awesome Youtube Channel with lots of great stuff about fly fishing WA as well as a lot of other places.